A VOF scheme is used to simulate interface between liquid phase and gas phase of an air-water stratified flow and a wavy interface is obtained (Two-dimensional simulation). If we consider the wavy interface as a wave, then here comes my qeustions: (1) What are the errors (or uncertainties) of the simulated wavelength and wave amplitude? If we could consider the mesh size in the wavelength direction as the error of the wavelength and the mesh size in the wave amplitude direction as the error of the wave amplitude? (2) The simulated wave peak is very small, smaller than the mesh size in both directions, i.e., the wave peak is held within one cell (control volume). I wonder how come this happens if the interface is obtained through the interpolation of adjacent meshes? In order words, in the simulation some small wave features be resolved and the scales of these small features are smaller than the mesh sizes in both directions, how could this happen?